Well drilling tool



1933- J. c. WRIGHT WELL DRILLING TOOL Filed Jan. 8, 1932 2 Sheets-Sheet 1 TQW ig I 1 fiir 9 70/09 Dec. 5, 1933 J. c. WRIGHT WELL DRILLING TOOL Filed Jan. 8, 1932 2 Sheets-Sheet 2 Patented Dec. 5, 1933 hurrah srArEs WELL DRILLXNG TOOL Jesse C. Wright, Huntington Park, Calif., as-

signor to Globe Oil Tools Company, Los Nietos, Oalif., a. corporation of California Application .Ianuary 8; 1932. Serial No. 585,470 1 2 Claims.

This invention relates to a Well tool and relates more particularly to a well drilling bit. A general object of the present invention is to provide a simple, practical, effective well drilling bit having a cutting part or blade that is automatically fed or advanced relative to its support or backing as it Wears during the drilling operation.

An object of the invention is to provide a well drilling bit in which the cutting part is automatically fed or advanced downwardly relative to its support or backing as it wears, to at all times have an eifectivev cutting edge exposed, and to at all times be efificiently hacked and supported.

It is another object of the invention to provide a well tool of the character. mentioned in which the means for obtaining the relative advancement of the cutting part or cutting-blade is yielding, so that the cutting part or cutting blade automatically retracts when subjected to excessive feed pressures and is therefore not liableto breakage or distortion from overload- 1ng.

Another object of the invention is to provide a well bit of the character mentioned inwhich the cutting blade projects-only a short distance from its support, or backing during. operation to be eficientin acting on the formation and to the backing so that it is not liable to break or become distorted.

Another object of the invention is to provide a bit of the character mentioned in which the cutting part or cutting blade is replaceable.

Another object of the invention is to provide a well drilling bit in which the cutting action of the cutting part ceases or is materially lessened immediately upon the cutting part Wearing a certain amount so that the driller is informed or becomes aware when the cutting part requires replacement.

Another object of the invention is to provide a well drilling bit of thecharacter mentioned in which the cutting part or cutting blade is simple in formation and therefore inexpensive of manufacture.

A further object of the invention is to provide an embodiment in which the relative advancement of the cutting part or cutting blade is obtained by fluid pressure means.

Further objects and features of the invention will be best and more fully understood by the following detailed description of typical forms and applications of the invention, during which have its major portion effectively supported by description reference is had to the accompanying drawings, in which:

Fig. 1 is a side elevation of one embodiment of the invention. Fig. 2 is a central longitudinal detailed sectional view of the tool illustrated in Fig. 1. Fig. 3 is a transverse detailed sectional, view taken as indicated by line 3--3jon Fig. 1. Fig. 4 is a bottom elevation of the tool disclosed in Fig. 1. Fig. 5 is a side elevation of another embodiment of the invention. Fig. 6 is a vertical detailed sectional view taken as indicated by line 66 on Fig; 5. Fig. 7 is a bottom elevation of the bit illustrated in Fig. 5. Fig. 8 is a transverse detailed sectional view taken as indicated by line 88 on Fig. 5. Fig. 9 is a fragmentary vertical detailed sectional view of a fluid pressure means for advancing the blade.

Theform of the invention illustrated in Figs. 1110 4 inclusive of the drawings, includes, generally, two elements, a shank or body 10, and a cutting part or blade 11, and means for automatically feeding or advancing one or the elements relative to the other.

In the typical embodiment of the invention illustrated in Figs. 1 to 45 of, the drawings, the shank or body-10 is the relatively stationary elementwhilethe cutting blade 11 is the movable element and is advanced relative to the shank 10 bythe means 12. The shank or body 10 forms. the support and backing for the cutting blade 11 and houses the feeding means 12. In accordance with the broader aspects of the in: vention, the shank 10 may be varied considerably in shape. In the particular case disclosed in' the drawings, the shank or body 10 is an elongated member of round horizontal cross section. Suitable means is provided at the upper end. of the shank 10 for connection with an operating string. In the case illustrated in the drawings, a taperedscrew threaded socket 13 is. provided in the upper end of the shank 10 to receive a connecting part on an operating string of drill. pipe, or the like. The lower end of the bodyor 10 is preferably flat and normal to, the vertical axis of the shank to effectively takethe weight of the .drilling tools, or take the feed pressure in the event that the feed pressures are excessive, or in the event that the cutting blade ll is worn to a great extent Th cutting part or cutting blade 11 is a comparatively thin member formed of hard cutting material. 7 The blade 11 extends into a diametric slot 14 in the lower end of the shank 10; In. cc rd nce with the invention, the cutting blade 11 is slidable or movable vertically in the slot 14. The cutting blade 11 has flat parallel sides to effectively bear on the side walls of the slot 14. Under normal working conditions, the cutting blade 11 projects downwardly a short distance from the lower end of the body 10 and projects laterally from opposite sides of the body to act on the formation in the well bore. The cutting edges of the blade 11 may be shaped and formed as desired. In the particular case illustrated in the drawings, the lower end of the blade 11 has the configuration of a typical fish tail bit or cutter, and the side cutting edges 15 of the blade are straight and substantially vertical.

The invention includes means for guiding the blade 11 for vertical movement relative to the shank l0 and for preventing horizontal or lateral movement and displacement of the blade. A centralstem or boss 16 projects from the upper end of the blade 11. The boss 16 is of round cross section and is slidable in a central longi tudinal opening 17 in the shank 10. The slot 14 and the cutting blade 11 are sufiiciently long and are related to permit substantial relative movement between the blade 11 and the shank 1G. The upper end of the slot 14 limits upward movement of the blade relative to the shank. A screw 18 is provided on the upper end of the boss 16 and has an enlarged head slidable in a longitudinal opening 19 in the shank 10. The screw 18 is adapted to engage the lower end of the opening, 19 to limit downward movement of the blade relative to the body 10.

The means 12 for actuating the cutting blade 11 or for automatically feeding the blade 11 relative to the shank 10 operates to urge the blade 11 downwardly to project from the lower end of the shank 10 to effectively act on the-formation in the well bore. In accordance with the invention, the actuating means or feeding means 12 is yielding to allow for retraction of the blade 11 relative to the body 10 when the bit is subjected to excessive or heavy feed pressures. In ,he particular embodiment of the invention being described, the feed means 12 is in the nature of a spring means including a helical spring 20 carried in the opening 19. The spring 20 is arranged under compression between the upper end of the screw 18 and a plug 21 closing the upper end of the opening 19. The spring 20 is preferably comparatively heavy or strong to cause the cutting blade 11 to efiectively cut or dig into the formation. If the feed pressures placed on the bit are too heavy, the spring 20 yields so thatthe blade 11 retracts into the slot 14, or in other words, so that the body 10 moves downwardly relative to the blade 11 to have its lower end engage the formation atthe bottom of the bore and take the excessive feed pressures. In this manner, the yielding feed means 12 prevents fracture or distortion of the cutting blade 11 from overloading of the bit.

The invention includes means for handling circulation fluid. Passages 22 extend downwardly from the lower end of the socket 13 and discharge at the lower end of the shank 10. The fluid passages 22 may be inclined to discharge toward or against the forward faces of the cutting blade 11 so as to effectively flush the blade.

In operation the bit is mounted on the lower end of an operating string of drill pipe, or the like, and is rotated in the well bore so that the cutting blade 11 shears the formation. The feed L pressures on the tool cause the spring 20 to yield a certain extent so that the blade projects from the lower end of the body only sufdciently to have effective cutting action. The strength of the spring may be readily determined so that the proper feed pressures may be used in operating the tool. In the event that the feed pressures or the weight of tools placed in the bit becomes excessive, the spring 20 yields, allowing the blade 11 to be completely received in the slot 14 so that it is not subject to breakage. The driller is immediately made aware of the fact that the feed pressures are excessive, as the cutting action stops when the lower end of the shank 10 engages the bottom of the bore. In this manner, the cutting blade 11 cannot be subjected to excessive pressures. As the cutting blade 11 wears, the spring 20 automatically forces it down relative to the shank 10 so that an effective cutting edge portion of the blade always projects downwardly from the shank 10. The walls of the slot 14 form eifective supports or backing for the blade 11 and maintain the blade in the vertical position. The blade 11 is readily replaceable, as the plug 21, spring 20 and the screw 18 may be readily removed from the opening 19 to allow removal of the cutting blade 11 downwardly from'the slot 14. The cutting blade 11 is a simple plate of hard cutting material and is accordingly inexpensive of manufacture. The tool is particularly simple, and. very effective in operation.

The embodiment of the invention disclosed in Figs. 5 to 8 inclusive of the drawings includes, generally, two relatively movable parts, namely, a shank or body 10 and the cutting blade 11*, andmeans 12 for automatically advancing or feeding one of'the elements relative to the other as wear occurs during the drilling operations.

The shank 10 is the relatively stationary element of the tool, while the cutting blade 11 is the relatively movable element, and is fed or advanced by the means 12 The shank IO 'may be similar to the shank 10 described above, that is, it may be an elongated cylindrical member. A screw-threaded socket 24 may be provided in the upper end of the shank 10 to facilitate at tachment of the tool to the lower end of an operating string. The lower end portion of the shank 10 is shaped to receive or carry the cutting blade 11 and forms the backing for the relatively movable cutting part or blade. Two opposite quarters or segments 25 of slightly less than 90 project downwardly from the lower end of the shank 10 The sides of the two like segments 25 are fiat and vertical, while the lower ends of the segments are normal to the longi-- tudinal axis of the bit.

The movable element or cutting blade 11 is a comparatively thin plate-like part of hard cutting material. laterally staggered or offset portions 26 slidably bearing against the forward faces of the two segments 25. Means is provided for guiding the blade 11 and for maintaining the blade in bearing engagement with the segments 25. The guiding and retaining means is in the nature of a dove-tailed tongue and groove connection. In the typical embodiment illustrated in the drawings, dove-tailed tongues 27 are provided on The cutting blade 11- has two 171% the inner sides of the cutting blade portions 25 11? to slidably cooperate with vertical grooves 28 in the forward faces of the segments 25. During construction of the tool the forward faces of the grooves 28 may be readily machined.

races of the blade 11 The cutting blade 11 normally-projects from the lower end of 'the'shank 10 that is, it projects below the segments 25 and also projects from opposite sides of the shank. Thelower end of the cutting blade 11 may be sharpened and shaped as desired. 7

A central stem or boss 29 is provided on the upper end of the cutting blade ll and isslidable in a vertical opening 80 in the shank 10 A screw 31 is provided on the upper end of the boss 29 and is slidable in an enlarged opening 32, extending downwardly from the base of the socket 24. The screw 31 is adapted to engage the bottom or" the opening 32 to limit downward movement of the blade 11 The upward movement of the blade 11 is limited by downwardly facing shoulders 33 at the upper ends of the segments 25. Detachable blocks or segments 34 are provided on the shank 10% at the forward The blocks 34 may be attached to the segments 25 by counter-sunk screws 35. The blocks 34 are preferably shorter than the integral segments 25. It will be apparent that the cutting blade 11 is slidable between the segments 25 and the blocks 34.

Means are provided for discharging circulation fluid from the lower end portion of the shank 10 to flush the cutting blade 11 Fluid passages 36 extend downwardly from the bottom of the socket 24 and communicate with discharge openings 3'7 in the blocks 34. The openings 37 extend downwardly through discharge bosses 38 at the lower ends of the blocks 34 and discharge at the forward cutting faces of the blade 11*. The blocks 34 carrying the discharge bosses 38 provide for the discharging of circulation fluid at points immediately adjacent the cutting edges or" the blade 11 when the blade is in operation;

The means 12 for automatically advancing or feeding the blade 11 downwardly as it wears off during the drilling operation may be similar to or identical with the means 12 just described. In the case illustrated in the drawings, the means 12 includes a coil spring 40 arranged in the opening 32 under compression between the screw 31 and a plug 41 closing the upper end of the opening. The spring 40 is sufliciently strong to force the cutting blade 11 into efficient cutating action with the formation. The spring 40 yields when excessive pressures are placed on the tool, to permit relative movement between the blade and body 10 and allow the body 10 to assume the excessive pressures.

The operation of the form of the invention illustrated in Figs. 5 to 8 is like the operation of the embodiment first described. The blade 11 is effectively backed up by the segments 25 and is guided for vertical movement by the dove-' tailed sliding connections 2?-28. The spring 40 acts to automatically feed the hard cutting blade 11 downwardly relative to the shank 1G as the blade wears through use. Accordingly the tool is self-sharpening. Upon the cutting blade 11 becoming excessively Worn, the screw 31 limits further downward feeding of the blade and the lower end of the shank 10 en ages the bottom oi the well bore. When this occurs, the driller becomes aware that the blade is worn and may replace the blade. 7

Fig. 9 of the drawings illustrates a fluid pressure actuating means or iiuid pressur feed means for advancing the cutting blade that may be embodied the forms of the invention dise closed in Figs. 1 to 5 and Figs. 5 to 8 in substitution for the spring means described above.

The fluid pressure feed means includes a fluid opening or cylinder opening provided in the shank or body 10 and a piston 51 connected with the cutting blade 11 and operable in the cylinder opening 50. 1

Thebody 10 may be similar to or identical with the bodies 10 or 10 describedabove. In the particular case illustrated in the drawings, a screw-threaded socket 52' is provided in the upper end of the body 10 to facilitate attach-" merit of the bit to an operating string. The cylinder opening 50 communicates with the low er end of the socket 52and extends downwardly from the socket; In this-"manner the cylinder opening 50 is in communication with the oper ating string or drill pipe passing the circulation fluid. An opening 53 or reduced diameter connects. the cylinder opening 50 and the slot or opening 54 slidably carrying the cutting blade ll The cutting blade 11 is slidably vertical in the opening 54 and is provided at itsupper end with a stem or rod '55. longitudinally through the opening 53 and projects into the cylinder opening 5 a The piston 51 is mounted on the upper end of the rod 55 and is provided to slidably engage the walls of the c linder opening 50. A tubular 'nut or nipple 55 may be provided in the upper end of the cylinder opening 50 to limit upward movement of the piston 51. The piston51 is adapted to be operated downwardly by pressure on the circulation fluid in the cylinder opening 50 to advance or feed the cutting blade 11 Branch circulation passages 56 extend downwardly from the lower end of the cylinder opening 50 to discharge at the lower end of the shank 10 A longitudinal opening 57 is pro The rod 55 extends vided in the piston 51 to pass fluid from the upper end of the cylinder opening 50 to the discharge passages 56 A recess 58 may be provided in the lower end of the cylinder opening 50 to communicate with the upper end of the branch passages 55 so that the lower walls of the cylinder opening 50 will not close the opening 57.

I Pressure on the downwardly flowing circulation fluid acts on the piston 51 to urge. the cutting blade 11 downwardly and feed it from the lower end of the shank 19 The pressure on the fluid may be varied to suitdiiferent operating conditions, etc. The feeding or advancement of the cutting blade l1 may be constant oruniform by maintaining a uniform pressure on the circulation fluid.- In the event that the feed pressure on the bit becomes excessive, the

cutting or operating thrusts on the blade 11 may overcome the fluid pressure on the piston 51 and cause retraction of the blade into the slot .54.- It is to be noted that the fluid pressure means51 does not prevent the discharge of fluid at the lower end of the bit. It is believed that it will be apparent how the fluid pressure blade feeding means just described "may be readily embodied in the previously described forms of the invention in substitution for the spring means. The fluid pressure feeding means is readily controllable from the surface by varying the pressure on the circulating fluid, and the feed pressures or weight of the drilling tools placed on the bit may be related to the pressure Cir the body as it wears. The feed means is such that only a comparatively small cutting portion of the blade need be exposed during operation. The major portion of the cutting blade is efiectively supported against the cutting thrusts so that it is not subject to failure or distortion. The cutting blade may be formed sufliciently long to provide for the operation of the tool over a long period of time. The cutting blade may be easily replaced when desired and is such that it is comparatively inexpensive of manufacture.

Having described only typical preferred forms of my invention, I do not wish to limit myself to the specific details set forth, but which to reserve to myself any changes or variations that may appear to those skilled in the art or fall within the scope of thefollowing claims:

Having described my invention, I claim:

1. A well bit including a body having projections on its lower end, there being spaced fluid passages in the body and dove-tailed grooves in the forward sides of the projections, a cutting blade having its rear side slidably engaging said sides of the projections, dovetailed tongues on the blade slidable in the grooves, blocks attached to the body and slidably engaged by the forward side of the blade, bosses on the lower ends of the blocks, there being fluid passages in the blocks communicating with the passages in the body and discharging fluid from the bosses to flush the forward faces of the blade, and means for feeding the blade downwardly.

, 2. A well bit including, a body having a threaded socket in its upper end for receiving a part of an operating string, a reduced opening extending downwardly from the socket, and a transverse slot joining said opening and extending to the lower end of the body, a cutting blade slidable in the slot and adapted to project from the lower end of the body, a stem on the cutter slidable in said opening, a plug closing the upper end of said opening, and a spring in the opening under compression between the plug and the end of the stem for urging the blade downwardly.

' JESSE C. WRIGHT. 

